The present disclosure relates generally to power transfer mechanisms and, more particularly, to a multichannel, contactless power transfer system for a computed tomography (CT) system.
Computed tomography (CT) systems are used to obtain non-invasive sectional images of test objects, particularly internal images of human tissue for medical analysis and treatment. Current CT systems position the test object, such as a patient, on a table within a central aperture of a rotating frame, or gantry, which is supported by a stationary frame. The gantry includes an x-ray source and a detector array positioned on opposite sides of the aperture, within an x-y plane of a Cartesian coordinate system (generally referred to as the “imaging plane”), such that both rotate with the gantry around the test object being imaged. At each of several angular positions along the rotational path of the gantry (also referred to as “projections”), the x-ray source emits a fan-shaped collimated beam that passes through the imaging slice of the test object, is attenuated by the test object, and is received by the detector array.
Each detector element in the detector array produces a separate electrical signal indicative of the attenuated x-ray beam intensity, the beam projected from the x-ray source to the particular detector element, incident at its sensor surface. The electrical signals from all the detector elements are collated by circuitry within the rotating frame to produce a projection data set at each gantry angle or projection. Each projection data set is referred to as a “view”, and a “scan” is a set of such views from the different gantry angles during one revolution of the x-ray source and detector array. The scan is then processed by a computer in the stationary frame to reconstruct the projection data sets into a CT image of the slice or cross-section of the test object.
In a conventional CT system, power is transferred across a brush and slip ring mechanism to an inverter, which physically rotates with the gantry along with a high-voltage tank circuit (e.g., including transformer, rectifier, and filter capacitance components) of the CT system. Unfortunately, placing the inverter on the rotational gantry increases the weight, volume and complexity of the system. Furthermore, brush and slip ring mechanisms (which are typically used to carry appreciable current) are subject to reduced reliability, maintenance problems, and electrical noise generation, which interferes with sensitive modern medical diagnostic procedures, especially in harsh environments.
Accordingly, as higher rotational speed CT systems are developed, it becomes advantageous to reduce the volume and weight of the rotating components.